Some example embodiments relate to detecting symbols encoded in a Multiple-Input Multiple-Output (MIMO) spatial multiplexing transmission.
Multiple-Input Multiple-Output (MIMO) spatial multiplexing increases spectrum efficiency according to the number of antennas for communication. Before decoding symbols encoded in a received MIMO spatial multiplexing transmission, a MIMO receiver detects the symbols in the transmission. For example, maximal likelihood solutions are used to detect the symbols encoded in MIMO spatial multiplexing transmissions.
Finding a maximal likelihood solution involves searching a lattice of points in a multi-dimensional space. The points in the lattice correspond to each possible symbol vector made up of every possible combination of symbols for a given encoding scheme (also referred to herein as a “constellation”). Accordingly, the number of points in the lattice is dependent upon the number of symbols in the symbol vector (also referred to herein as the number of “spatial streams”) and the number of possible symbols in the encoding scheme. Hence, the complexity of finding the maximal likelihood solution is in the order of O(ML), where M is the size of the constellation and L is the number of spatial streams, assuming equal modulation order over all spatial streams.